Raloxifene rebound regression.

The first case of clinical remission of metastatic breast after the withdrawal of raloxifene is reported. A postmenopausal woman was treated for stage II breast cancer with a modified radical mastectomy and adjuvant cyclophosphamide, doxorubicin, and 5-flurouracil followed by tamoxifen for 5 years. One year following the cessation of tamoxifen, osteopenia was noted and raloxifene was begun. Two years following the start of raloxifene, supraclavicular adenopathy and lung metastases developed, which regressed after discontinuation of raloxifene. Although raloxifene is not frequently given to women with previous breast cancer, increasing use in osteopenic women may lead to cancer developing in these raloxifene-treated women; this despite the major reduction in the incidence of breast cancer in raloxifene-treated versus placebo-treated women. A clinically significant response to the withdrawal of a hormone, used either for the treatment of breast cancer or for some other reason, is not a rare event, and the therapeutic usefulness of observation only for a rebound regression is a frequently overlooked strategy in the treatment of breast cancer.